
We’re opening a research preview of Claude Duet, a new app where Claude works as a proactive agent.
It comes to you with what needs your attention, completes tasks you ask of it, keeps working when you step away, and checks with you before it acts on your behalf.
Boris Cherny retweeted
We launched OSS Scanner, which gives critical open source projects free, periodic vulnerability scans from our strongest models.
Each finding includes a proof-of-concept, and a patch where possible.
red.anthropic.com/oss-scanne…
Boris Cherny retweeted
In the next version of Bun
bun lint is a 26x faster ESLint-compatible linter with over 1,000 builtin rules - reads eslint & oxlint configs.

ALT Poster for bun lint, an ESLint-compatible linter built into Bun. Headline: 26x faster than ESLint. Table of lint times on real projects, each with its own config and plugins, bun lint vs ESLint: shadcn/ui 2.1 s vs 90.4 s (43x), chakra-ui 0.59 s vs 22.6 s (38x), vscode 15.8 s vs 404 s (26x), mastodon 6.6 s vs 100 s (15x), playwright 4.9 s vs 53.4 s (11x). On vscode, 9,823 of 9,826 messages are identical. 99.6% of ESLint's tests pass. 99.8% of oxlint's tests pass. 2x faster than oxlint with 3x less memory. 1,021 rules built in, including type-aware rules.
Boris Cherny retweeted
We keep improving performance across Claude, and you may have noticed it starts responding sooner!
Claude Code now gzips the conversation it sends on every turn, so it reaches the model faster. Cloud sessions also start up as soon as you start typing.
Don't sleep on Claude Slides. This is how I make slide decks now -- no more googling "iphone frame svg" like the old days
Try it: claude.ai/artifacts
I could not imagine being productive without Claude Code Review. It runs on all of my PRs, and catches almost every bug before it goes it. This is a piece of the secret sauce that lets the team and I move so quickly while raising the quality bar
Over the last few years, we have made significant progress on prompt injection for Claude models. As agents do more, it is increasingly urgent that we solve it across the industry.
Really excited to partner with Gray Swan to host this competition. Can’t wait to see what you find!
Is prompt injection solved? Here’s $300,000 to find out.
In partnership with @AnthropicAI, @Meta, @GoogleDeepMind, @Reflection_ai and our other frontier lab sponsors, @GraySwanAI is excited to announce the largest and most realistic AI red teaming challenge to date.
Indirect Prompt Injection: Black ⚫
Boris Cherny retweeted
Hi, I'm Felix. I'm an eng lead working on Claude. I love watching people take flight and do things they never thought possible.
We often describe that as "being more ambitious" when using AI, which is tricky advice to follow. I wrote a tutorial:
felixrieseberg.com/how-to-be…
Boris Cherny retweeted
What did @AnthropicAI do with his latest Claude Desktop update? I feel like there was a major system prompt/harness upgrade here. Opus 5.5 feels like it's Opus 5.8 now.
cc @trq212 what did y'all do?
Boris Cherny retweeted
We've been working hard on making the Claude Code desktop app great for running lots of sessions side by side.
It's now much quicker to start sessions, easier to split work across a few, and you can always see what each of them is doing. Here’s what's new:
Boris Cherny retweeted
New on our Engineering blog: Creating in-house source control.
In May, we merged around 2,500 code changes per day. In September, we merged more than 30,000 per day. As a result, we became bottlenecked by developer infrastructure built for human (rather than agent) scale.
Here, we share how we built a new version control system—and fully migrated our monorepo from git—in five months: anthropic.com/engineering/re…
Boris Cherny retweeted
We just let in every Pro and Max user from the Claude Code Projects waitlist!
If you're new to Claude Code Projects, here's a 4 minute walkthrough to get you started:
Boris Cherny retweeted
people really like the versions of Claude Design and Slides built into Claude — usage is much higher.
we're doubling down there and folding standalone Design into Claude on December 14.
before then — PLEASE tell me all the reasons the new one falls short and we'll fix em!















